A vehicle occupant restraint device, such as an inflatable air bag module, located in the hub of a vehicle steering wheel is well known in the art. Such an air bag module typically includes an inflatable vehicle occupant restraint (or air bag), an air bag inflator for providing inflation fluid to inflate the air bag, a mounting plate for securing the air bag and the inflator to the hub of the steering wheel, an air bag cover, and a device to actuate the inflator. The air bag cover is rupturable upon inflation of the air bag.
Air bag modules are made so that a complete air bag module is insertable into the open hub of a steering wheel and the air bag cover conforms with the upper surface of the steering wheel.
It is customary to insert the air bag module into the open face of the steering wheel while the steering wheel is mounted on the steering column of the motor vehicle being assembled on a motor vehicle assembly line.
Some examples of patents that teach the assembling of air bags in the hub area of a steering wheel while the steering wheel is mounted on the steering column of a motor vehicle include U.S. Pat. No. 3,944,250 to Wulf et al. This patent teaches an inflatable gas cushion defined by a bag with a gas generating means mounted in the hub area of a steering wheel of a motor vehicle after the steering wheel is mounted on the steering column of the motor vehicle.
Other patents such as U.S. Pat. No. 5,280,746 to Adams et al., U.S. Pat. No. 5,294,147 to Edge, U.S. Pat. No. 5,314,203 to Adams et al., U.S. Pat. No. 5,356,173 to Hongou et al., and U.S. Pat. No. 5,358,270 to Kuretake et al. teach various air bag assemblies and/or the installation of an air bag assembly in a steering wheel while the steering wheel is mounted on the steering column of a motor vehicle.
In assembly line production of motor vehicles in motor vehicle assembly plants, the assembly sequence includes the assembly of the steering mechanism, including installation of the steering column, and the mounting of the steering wheel onto the steering column. The air bag assembly, or module, is then mounted into the hub of the mounted steering wheel through the open upper surface or face of the steering wheel.
After an air bag mounted in the steering wheel has been deployed, the air bag module must be removed from the steering wheel and replaced. This is accomplished by removing the complete air bag module from the steering wheel, while the steering wheel remains mounted on the steering column, and inserting a replacement module.